Structure for a robotic end effector

ABSTRACT

Various stabilization devices for a robotic end of arm tool, such as a robotic gripper, are described. The stabilization device is provided in a palm area of the end of arm tool and serves as a backstop against which actuators of the end of arm tool can push a compliant or slick target object. The stabilization device may take many any of a variety of shapes, depending on the application. Based on the shape of the stabilization device and the action of the robotic gripper on the target object, the target object can be moved or rotated in a more stable configuration, thus allowing the actuators to apply less force while still maintaining a firm grasp of the object.

RELATED APPLICATIONS

This application claims priority to: U.S. Provisional Patent ApplicationSer. No. 62/492,627, entitled “Structure for a Robotic End Effector” andfiled on May 1, 2017; and to U.S. Provisional Patent Application Ser.No. 62/643,859, entitled “Keels and a Method for Use” and filed on Mar.16, 2018; and to U.S. Provisional Patent Application Ser. No.62/644,690, entitled “New Keels and a Method for Use” and filed on Mar.19, 2018. The contents of the aforementioned applications areincorporated herein by reference.

BACKGROUND

This disclosure relates generally to the field of robotics, andparticularly to novel structures suited to assisting robotic endeffectors in grasping particularly compliant objects, such as baggeditems.

Conventionally, a robotic end effector may include a number of roboticfingers that grasp a target. Typically, the target is grasped betweenthe fingers and then moved from place to place. When lifting a compliantobject, such as an object in a bag or loose wrapping, the object mayslip out of the fingers' grasp when lifting the object, accelerating, ordecelerating. This problem can be compounded when the bag or wrapping isfilled with a product that is capable of shifting within its container;during movement of the object, the shifting of the product can causeforces to be applied unevenly to the bag or wrapping, making it moredifficult to securely grasp the target.

Consequently, the objects must be grasped relatively tightly by thefingers to avoid slipping or shifting of the target. This can damage theproducts contained in the bag or wrapping, and may not guarantee thatthe objects will not continue to slip or shift.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1D depict examples of soft robotic actuators suitable for usewith exemplary embodiments described herein.

FIGS. 2A-2D depict examples of stabilization structures for robotic endof arm tools.

FIGS. 3A-3B depict an exemplary stabilization structure employed tograsp a target compliant object.

FIGS. 4A-4J depict various stages in the grasping process, showinginteractions between the stabilization structure, the target object, andthe actuators.

FIG. 5 is a flowchart depicting an exemplary method for grasping atarget compliant object.

FIG. 6 depicts the target object in a grasped configuration.

FIGS. 7A-7F depict various alternative configurations for thestabilization structure.

FIGS. 8A-8B depict a stabilization structure having two ridges forgrasping and a securing device for securing the stabilization structureto a robotic end effector.

FIGS. 9A-9C depict alternative configurations for the stabilizationstructures with respect to the distal ends of the robotic actuators.

FIGS. 10A-10D depict an alternative grasping process for grasping acompliant object.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more with reference to theaccompanying drawings, in which preferred embodiments of the inventionare shown. The invention, however, may be embodied in many differentforms and should not be construed as being limited to the embodimentsset forth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. In the drawings,like numbers refer to like elements throughout.

Background on Soft Robotic Grippers

Conventional robotic actuators may be expensive and incapable ofoperating in certain environments where the uncertainty and variety inthe weight, size and shape of the object being handled has preventedautomated solutions from working in the past. The present applicationdescribes applications of novel soft robotic actuators that areadaptive, inexpensive, lightweight, customizable, and simple to use.

Soft robotic actuators may be formed of elastomeric materials, such asrubber, coated fabric, or thin walls of plastic arranged in an accordionstructure that is configured to unfold, stretch, twist, bend, extendand/or contract under pressure, or other suitable relatively softmaterials. As an alternative or in addition to accordion structures,other types or configurations of soft actuators employing elastomericmaterials may be utilized. They may be created, for example, by moldingor bonding one or more pieces of the elastomeric material into a desiredshape. Alternatively or in addition, different pieces of elastomericmaterial may be thermally bonded, or sewn. Soft robotic actuators mayinclude a hollow interior that can be filled with a fluid, such as air,water, or saline to pressurize, inflate, and/or actuate the actuator.Upon actuation, the shape or profile of the actuator changes. In thecase of an accordion-style actuator (described in more detail below),actuation may cause the actuator to curve or straighten into apredetermined target shape. One or more intermediate target shapesbetween a fully unactuated shape and a fully actuated shape may beachieved by partially inflating the actuator. Alternatively or inaddition, the actuator may be actuated using a vacuum to removeinflation fluid from the actuator and thereby change the degree to whichthe actuator bends, twists, and/or extends.

Actuation may also allow the actuator to exert a force on an object,such as an object being grasped or pushed. However, unlike traditionalhard robotic actuators, soft actuators maintain adaptive properties whenactuated such that the soft actuator can partially or fully conform tothe shape of the object being grasped. They can also deflect uponcollision with an object, which may be particularly relevant whenpicking an object off of a pile or out of a bin, since the actuator islikely to collide with neighboring objects in the pile that are not thegrasp target, or the sides of the bin. Furthermore, the amount of forceapplied can be spread out over a larger surface area in a controlledmanner because the material can easily deform. In this way, soft roboticactuators can grip objects without damaging them.

Still further, soft actuators are adaptive, and accordingly a singlefixture can grip multiple kinds of objects. Because the outer surfacesof soft actuators are relatively delicate, they can serve in roles suchas redirectors for easily bruised or damaged items (e.g., tomatoes)whereas hard fixtures might be limited to manipulating more robust items(e.g., brass valves).

Furthermore, soft actuators will typically not mark the surface beinggripped. Typically, when an easily-marked surface (e.g., a veneer) willbe gripped by a hard fixture, a protective coating or film may beapplied to prevent the part from being marked; this increases the costof manufacturing. With a soft actuator, this step may be omitted and thepart may be protected without a special coating or film.

Moreover, soft robotic actuators allow for types of motions orcombinations of motions (including bending, twisting, extending, andcontracting) that can be difficult to achieve with traditional hardrobotic actuators.

FIGS. 1A-1D depict exemplary soft robotic actuators. More specifically,FIG. 1A depicts a side view of a portion of a soft robotic actuator.FIG. 1B depicts the portion from FIG. 1A from the top. FIG. 1C depicts aside view of a portion of the soft robotic actuator including a pumpthat may be manipulated by a user. FIG. 1D depicts an alternativeembodiment for the portion depicted in FIG. 1C.

An actuator may be a soft robotic actuator 100, as depicted in FIG. 1A,which is inflatable with an inflation fluid such as air, water, orsaline. The inflation fluid may be provided via an inflation device 120through a fluidic connection 118.

The actuator 100 may be in an uninflated state in which a limited amountof inflation fluid is present in the actuator 100 at substantially thesame pressure as the ambient environment. The actuator 100 may also bein a fully inflated state in which a predetermined amount of inflationfluid is present in the actuator 100 (the predetermined amountcorresponding to a predetermined maximum force to be applied by theactuator 100 or a predetermined maximum pressure applied by theinflation fluid on the actuator 100). The actuator 100 may also be in afull vacuum state, in which all fluid is removed from the actuator 100,or a partial vacuum state, in which some fluid is present in theactuator 100 but at a pressure that is less than the ambient pressure.Furthermore, the actuator 100 may be in a partially inflated state inwhich the actuator 100 contains less than the predetermined amount ofinflation fluid that is present in the fully inflated state, but morethan no (or very limited) inflation fluid.

In the inflated state, the actuator 100 may exhibit a tendency to curvearound a central axis as shown in FIG. 1A. For ease of discussion,several directions are defined herein. An axial direction passes throughthe central axis around which the actuator 100 curves, as shown in FIG.1B. A radial direction extends in a direction perpendicular to the axialdirection, in the direction of the radius of the partial circle formedby the inflated actuator 100. A circumferential direction extends alonga circumference of the inflated actuator 100.

In the inflated state, the actuator 100 may exert a force in the radialdirection along the inner circumferential edge of the actuator 100. Forexample, the inner side of the distal tip of the actuator 100 exerts aforce inward, toward the central axis, which may be leveraged to allowthe actuator 100 to grasp an object (potentially in conjunction with oneor more additional actuators 100). The soft robotic actuator 100 mayremain relatively conformal when inflated, due to the materials used andthe general construction of the actuator 100.

The actuator 100 may be made of one or more elastomeric materials thatallow for a relatively soft or conformal construction. Depending on theapplication, the elastomeric materials may be selected from a group offood-safe, biocompatible, or medically safe, FDA-approved materials. Theactuator 100 may be manufactured in a Good Manufacturing Process(“GMP”)-capable facility.

The actuator 100 may include a base 102 that is substantially flat(although various amendments or appendages may be added to the base 102in order to improve the actuator's gripping and/or bendingcapabilities). The base 102 may form a gripping surface that grasps atarget object.

The actuator 100 may include one or more accordion extensions 104. Theaccordion extensions 104 allow the actuator 100 to bend or flex wheninflated, and help to define the shape of the actuator 100 when in aninflated state. The accordion extensions 104 include a series of ridges106 and troughs 108. The size of the accordion extensions 104 and theplacement of the ridges 106 and troughs 108 can be varied to obtaindifferent shapes or extension profiles.

Although the exemplary actuator of FIGS. 1A-1D is depicted in a “C” oroval shape when deployed, one of ordinary skill in the art willrecognize that the present invention is not so limited. By changing theshape of the body of the actuator 100, or the size, position, orconfiguration of the accordion extensions 104, different sizes, shapes,and configurations may be achieved. Moreover, varying the amount ofinflation fluid provided to the actuator 100 allows the actuator 100 totake on one or more intermediate sizes or shapes between the un-inflatedstate and the inflated state. Thus, an individual actuator 100 can bescalable in size and shape by varying inflation amount, and an actuatorcan be further scalable in size and shape by replacing one actuator 100with another actuator 100 having a different size, shape, orconfiguration.

The actuator 100 extends from a proximal end 112 to a distal end 110.The proximal end 112 connects to an interface 114. The interface 114allows the actuator 100 to be releasably coupled to other parts of theactuator. The interface 114 may be made of a medically safe material,such as polyethylene, polypropylene, polycarbonate,polyetheretherketone, acrylonitrile-butadiene-styrene (“ABS”), or acetalhomopolymer. The interface 114 may be releasably coupled to one or bothof the actuator 100 and the flexible tubing 118. The interface 114 mayhave a port for connecting to the actuator 100. Different interfaces 114may have different sizes, numbers, or configurations of actuator ports,in order to accommodate larger or smaller actuators, different numbersof actuators, or actuators in different configurations.

The actuator 100 may be inflated with an inflation fluid supplied froman inflation device 120 through a fluidic connection such as flexibletubing 118. The interface 114 may include or may be attached to a valve116 for allowing fluid to enter the actuator 100 but preventing thefluid from exiting the actuator (unless the valve is opened). Theflexible tubing 118 may also or alternatively attach to an inflatorvalve 124 at the inflation device 120 for regulating the supply ofinflation fluid at the location of the inflation device 120.

The flexible tubing 118 may also include an actuator connectioninterface 122 for releasably connecting to the interface 114 at one endand the inflation device 120 at the other end. By separating the twoparts of the actuator connection interface 122, different inflationdevices 120 may be connected to different interfaces 114 and/oractuators 100.

The inflation fluid may be, for example, air or saline. In the case ofair, the inflation device 120 may include a hand-operated bulb orbellows for supplying ambient air. In the case of saline, the inflationdevice 120 may include a syringe or other appropriate fluid deliverysystem. Alternatively or in addition, the inflation device 120 mayinclude a compressor or pump for supplying the inflation fluid.

The inflation device 120 may include a fluid supply 126 for supplying aninflation fluid. For example, the fluid supply 126 may be a reservoirfor storing compressed air, liquefied or compressed carbon dioxide,liquefied or compressed nitrogen or saline, or may be a vent forsupplying ambient air to the flexible tubing 118.

The inflation device 120 further includes a fluid delivery device 128,such as a pump or compressor, for supplying inflation fluid from thefluid supply 126 to the actuator 100 through the flexible tubing 118.The fluid delivery device 128 may be capable of supplying fluid to theactuator 100 or withdrawing the fluid from the actuator 100. The fluiddelivery device 128 may be powered by electricity. To supply theelectricity, the inflation device 120 may include a power supply 130,such as a battery or an interface to an electrical outlet.

The power supply 130 may also supply power to a control device 132. Thecontrol device 132 may allow a user to control the inflation ordeflation of the actuator, e.g. through one or more actuation buttons134 (or alternative devices, such as a switch). The control device 132may include a controller 136 for sending a control signal to the fluiddelivery device 128 to cause the fluid delivery device 128 to supplyinflation fluid to, or withdraw inflation fluid from, the actuator 100.

Exemplary Structures for a Robotic End Effector

Exemplary embodiments relate to structures suitable for use with roboticend effectors or end of arm tools (EOATs) employing one or more roboticactuators. The exemplary structures improve grasp stability when theactuator(s) attempt to grasp relatively compliant objects such as baggeditems.

It is noted that, in the examples below, the stabilization structuresare described as being used in conjunction with soft robotic actuatorsas outlined above. However, although soft robotic actuators may provideadvantages when used with the stabilization structures, as alluded toabove and addressed in more detail below, it is understood that thepresent invention is not limited to use with soft robotic actuators.

Exemplary embodiments provide a centralized back-stop against which theactuator(s) may squeeze the bag or other product during grasping. Byusing the described structures, a lower pressure of inflation fluid maybe used in the actuators (resulting in a more delicate hold on thetarget object) while still maintaining an effective grasp on the targetobject.

FIG. 2A depicts an example of such a stabilization structure. Thestructure may be deployed on a base 202 of a robotic end effector, suchas on a grasper for a robotic arm, an end of arm tool (EOAT), or otherrobotic device capable of grasping a target object. For instance, theexemplary grasper of FIG. 2A includes two soft actuators 100. The base202 may be a portion of the robotic body or arm which is configured toreceive an end effector (e.g., through the use of fasteners or othersecuring devices), or the end effector may be integral with the roboticbody or arm.

As shown in FIG. 2A, the exemplary structure may be provided in acentralized location in a palm area 204 in proximity to one or moreactuators 100. The palm area 204 may be different on each end effector,depending on the configuration of the actuator(s) 100 or other graspingimplements, as well as other structures present on the end effector. Forinstance, in the two-actuator example of FIG. 2A, the palm area 204 mayextend from a base of one actuator 100 across the end effector to a baseof the other actuator 100 (in a left-to-right direction in FIG. 2A). Thepalm area 204 may further extend in other directions, such as along alength of the end effector. Particularly in the case in which multipleactuators 100 are aligned along a side of the end effector (see, e.g.,FIGS. 3A-3B), the palm area 204 may include the regions between theactuators in the length and width directions of the end effector. Inother embodiments, the end effector may employ only a single actuator100, in which case the palm area 204 may include the area extending in aradial direction perpendicular to the base of the actuator 100 when theactuator is in an uninflated state, and may include an area under thedistal end of the actuator 100 when the actuator is in an inflatedstate. Depending on the principal of operation, (e.g., as in theexamples shown in FIGS. 4A-4J and 10A-10D) the palm area 204 mightextend beyond the area under the distal tip(s) of the actuators, so thatthe stabilization structure may be provided in a position so that thedistal tip(s) push the target object into the stabilization structure,rather than curling around under the stabilization structure.

The stabilization structure may be provided primarily in the palm area204, although portions of the stabilization structure may extend beyondthe palm area 204 and the stabilization structure need not cover theentire palm area. Rather, the body 210 of the stabilization structureshould be sized, configured, and located so as to provide a backstopagainst which the actuator(s) 100 push the target compliant objectduring grasping, in accordance with the methodologies described below.

The stabilization structure, also referred to herein as a keel, may be arigid or semi-rigid structure around which the actuators may curl. Insome embodiments, the stabilization structure may be formed of rubber orrubber-coated plastic. In some embodiments, the stabilization structuremay be a soft robotic actuator 100.

In some embodiments, the stabilization structure may be provided withdifferent surface textures or materials. In some examples, thestabilization structure may be designed with a first texture or shape,and may be configured to accept one or more coverings or otherattachable structures to accommodate different textures or shapes. Forexample, the stabilization structure may be designed with a smoothplastic finish with blended curves (which may be particularlywell-suited to food-handling operations or other situations in whichcleaning the end effector is an important consideration), and may beprovided with one or more covers to provide different textures, shapes,levels of compliance, etc.

The stabilization structure may include a body 210 having a target area206 against which the grasping tips of the actuators 100 (e.g., an areaat the respective distal ends of the actuators) are configured toapproach or contact. The stabilization structure may be affixed to thebase 202 of the end effector and/or a base of the gripper via astabilization structure base 208 provided in the palm area 204.

The target area 206 may be defined by the stabilization structure'sprofile. In the example of FIG. 2A, the body 210 of the stabilizationstructure includes a first region 212 adjacent to the base 208, thefirst region having a relatively wide convex profile. The first region212 transitions to a second region 214 that is convex and has arelatively narrower profile. The second region 214 transitions into athird region 216 that includes a rounded external side. In operation,the actuators 100 may curl the ends of the target object to be graspedaround the body 210 of the stabilization structure, forcing anintermediate area on the target object into the convex second region214. The first region 212 serves to provide a larger surface area aroundwhich the ends can curl, while the third region 216 causes the targetobject to bend around itself. Thus, the size and shape of the thirdregion 216 may be selected based on the properties of the target object(e.g., being selected so as to allow a certain degree of bending forstability purposes, while not allowing for a greater degree of bendingthat could cause the target object to be damaged).

Different profiles may be employed depending on the shapes and/ortextures of target object that the end effector is designed to engagewith. The shape may therefore be selected based on product composition,and the stabilization structure may be configured to be releasablycoupled to a manifold assembly via the base 208 so that differentstructures may be swapped in order to reconfigure the end effector fordifferent types, sizes, weights, shapes, etc. of products.

Examples of different structure shapes are shown in FIGS. 2B-2D. FIG. 2Bdepicts a stabilization structure 218 having a rounded ridge ofrelatively constant thickness as a body 210, which rises out of thecentral region of the base 208. FIG. 2C depicts a stabilizationstructure 220 having a keyhole shape, in which the first region 212 isconcave, transitioning to a second region 214 that is convex at atransition point 222 (selected based on the properties of the object tobe grasped, to thereby provide a ridge around which the sides or ends ofthe target object may be curled). A third region 216 forms the top ofthe body 210 of the stabilization structure 210. FIG. 2D depicts astabilization structure 224 having a plurality of pyramid-shaped bumps226, which allow portions of the target object to fill in theinterstices between the bumps 226, thus allowing for a stronger grasp onthe target object.

The profile of the stabilization structure may be selected and optimizedbased upon many factors, such as (but not limited to) the amount ofcompliance in the system. For example, if there is robot wristcompliance along the axis of motion corresponding to the direction inwhich an object is initially lifted during a pick up maneuver, then theshape of the stabilization structure body 210 may be selected to work inconjunction with this compliance to engage with the product in anoptimized way.

Furthermore, if there is compliance in the stabilization structureitself or the base 208 of the stabilization structure, then the bodyshape 210 may be optimized around this compliance. This may allow thesystem to provide the desired level of contact force at the end effectorheight associated with grasping the product. One application for thisembodiment includes driving some amount of granular product out towardsthe ends of a bag to “stiffen” or “pack” the shifting product into thegrasp area on the bag. Consequently, the robot's grasp on the bag may befurther improved.

FIGS. 3A-3B depict an example of a multi-actuator robotic end effector.In this example, eight actuators 100 are arrayed along the outside edgesof an end effector base. A palm area is formed in the region of the endeffector base between the actuators 100. A base 208 of the stabilizationstructure occupies substantially all of the palm area, and a body 210 ofthe stabilization structure includes a first region with a relativelywide profile and a second region attached to the first region andincluding a relatively constant-width ridge.

As shown in FIG. 3B, the end effector is capable of moving a graspedobject 302 in a y-direction (along an axis of rotation of the actuators100), an x-direction perpendicular to the y-direction in the same planeas the y-direction, and can also be rotated in an r-direction. In someembodiments, the end effector may also be capable of moving in aZ-direction (e.g., towards the top and bottom of the page in FIG. 3B.

The exemplary stabilization structures described herein provide a numberof benefits, including:

-   -   Increasing stability of the actuators' grasp on the target        object during the grip phase;    -   Increasing stability of the actuators' grasp on the target        object subjected to X-, Y-, and R-axis acceleration;    -   Enabling lower inflation fluid pressure to be used for grasping        a bagged or compliant target object with the same or an improved        grasp stability and quality as compared to higher pressures        without the use of the structure; and    -   Providing the actuators with a backstop against which the target        object may be compressed.

FIGS. 4A-4J depict a grasping process and show a principle of operationof certain embodiments described herein. FIGS. 4A, 4C, 4E, 4G, and 4Idepict the entire end effector and grasped object 302 at various pointsin the process, while FIGS. 4B, 4D, 4F, 4H, and 4J depict the samestages with certain structures omitted so that the effect on the targetobject 302 can be observed more easily.

In use, a compliant target object 302 such as a bagged product may beprovided in a target area accessible to the end effector (FIGS. 4A-4B).Optionally, the actuators 100 may be subjected to reverse inflation(FIG. 4A) so as to move the distal tips of the actuators 100 away fromthe target object 302, thus allowing for a wider grasp (and allowing theend effector to be moved into position with a reduced chance that theactuators 100 will prematurely come into contact with the target object302, thus moving the target object 302 in an undesirable manner).

The end effector may be positioned in proximity to the target object 302and may make initial contact with the target object (FIGS. 4C-4D).Preferably, the end effector may be relatively centered over an axis ofthe target object 302. Optionally, at this stage, the actuators may besubjected to neutral inflation to move into a neutral position (FIG.4C). Preferably, the distal tips 110 of the actuators 100 may bepositioned at this stage so as to be outside of and/or under the edges404 of the target object 302.

The initial contact with the target object 302 may cause the targetobject 302 to slightly deform around the body 210 of the stabilizationstructure, causing a groove 402 to be formed in a central region of thetarget object (FIG. 4D). Depending on the shape and configuration of thestabilization structure other types of manipulations may also oralternatively occur upon contact with the stabilization structure.

Advantageously, this deforming/manipulation may allow the target objectto be re-shaped to a certain degree while the actuators 100 are heldopen, prior to grasping the object 302. This could result, for example,in the stabilization structure pressing a central lump in a baggedproduct into an indented groove (or between ridges, as shown for examplein FIGS. 8A-8B), which forces loose movable products in a bag toredistribute for a more favorable grasp. This may occur over a shortperiod of time between when the stabilization structure makes initialcontact with the target object 302 and when the actuators 100 inflateand initiate a grasp on the target object 302. Consequently,redistribution and grasping may happen almost concurrently, which allowsfor a relatively strong grasp in a relatively fast, efficient process.In comparison, without such a stabilization structure an end effectormight be forced to attempt to grasp the target object 302 as-is (i.e.,as it is shaped when presented to the end effector), which may lead tohighly variable grasping quality.

The actuators 100 may then be inflated, which pushes the edges 404 ofthe target object around the stabilization structure (FIGS. 4E-4H). Theend effector may then be lifted, rotated, translated, etc. while theactuators grasp the target object (FIGS. 4I-4J).

In a conventional end effector without the use of a stabilizationstructure, the actuators 100 would be required to grasp the targetwithout assistance, which can cause the target object to slip out of theactuators' grasp during relatively high acceleration or decelerationmovements. The stabilization structure shown in FIGS. 4A-4J serve totake some of the load from the acceleration of the target object, whichprovides an improved ability to resist the effects of acceleration onthe target object. A more detailed view of the end effector grasping atarget object is shown in FIG. 6.

Variations of the above-described embodiments (e.g., employing more orfewer actuators, actuators in different configurations, different sizesor shapes of end effectors, etc.) may also be utilized.

FIG. 5 describes a procedure for deploying and using an end effectorwith a stabilization structure.

At block 502, a robotic end effector may be provided. The robotic endeffector may be any device suitable for grasping or otherwisemanipulating a target object. The robotic end effector may include arobotic arm, a robotic grasper or hand, a robotic tentacle, anend-of-arm tool (EOAT), etc. The robotic end effector may be separatefrom the stabilization device, or may be integral with the stabilizationdevice. The robotic end effector may be at a fixed location, or may bemobile.

At block 504, a stabilization device may be selected for deployment onthe robotic end effector. The stabilization device may have a size,shape, texture, configuration, etc. specific to the stabilizationdevice, and a particular stabilization device may be selected based onthe context in which it is employed. Among other features, thestabilization device may be selected based on: a number, size, orconfiguration of actuators on the end effector; a size, shape, texture,etc. of an exterior surface of the target object; a compressibilityand/or degree of movement or shifting expected based on material on aninterior of the target object; a direction of movement of the targetobject once grasped, a weight of the target object; etc.

At block 506, the stabilization device may optionally be affixed to apalm area of the robotic end effector, if the stabilization device andend effector are not integral. The stabilization device may be affixedusing fasteners, such as bolts that pass through a base of the roboticend effector and a base of the stabilization device, and secured usingnuts (such as those shown in FIGS. 8A-8B). Alternatively or in addition,the stabilization device may be affixed using clamps, screws, pins, amagnetic attachment, suction, ties, mating grooves, tabs, or slots, orany other suitable fasteners.

At block 508, an inflation limit may be selected for soft actuators ofthe robotic end effector (alternatively, if hard actuators are used, amaximum extension limit may be defined). The limit may be defined basedon a target pressure to which the actuators should be inflated, a targetamount of force to be applied to the target object, a distance ofextension or degree of flexion desired of the actuator, etc.

Instead of a particular value, an acceptable inflation range may beprovided. According to some embodiments, the inflation limit maypreferably be in the range of 9-13 pounds per square inch (PSI). Inanother embodiment, the limit may be a range of values such that thelower end of the range corresponds to an amount of inflation/extensionthat would be barely sufficient to hold the target object through adesired movement sequence (e.g., a value determined empirically or bysimulation that maintains a grasp on the target object more than apredetermined percentage of times); the upper end may correspond to amaximum amount of inflation/extension such that furtherinflation/extension would cause damage to the product. In someembodiments, the inflation limit may be selected to correspond to adegree of deployment of the actuators such that, when the actuators aredeployed to the identified degree, the target object is secured to thestabilization device in a desired configuration (e.g., bent around thestabilization device by a desired amount, deformed or manipulated to acertain degree, etc.).

At block 510, the target object may be moved to a target location. Thetarget object may be moved, for example, into a position under therobotic end effector. In some embodiments, the target object may bemoved into position along a conveyor belt. In some embodiments, thetarget object may be provided to the target location in a predeterminedposition (e.g., so that the long axis of the target object is orientedin a predetermined direction), or may be manipulated by the end effectoror another device so as to be moved into the predetermined position oncethe target object is moved into the target location.

At block 512, the stabilization structure may be moved into proximitywith the target object. In some embodiments, this may involve makingcontact with the target object, while in others the stabilizationstructure may be moved to within a predetermined distance of the targetobject. The movement of the stabilization structure (and the endeffector to which it is attached) may be guided by various sensors, suchas proximity sensors, cameras, touch sensors, etc. In some embodiments,the end effector may be positioned in this block so as to be relativelycentered over an axis of the target object 302. The axis of the targetobject may represent a grasping axis along which the actuators may bearrayed (e.g., along a long axis of the stabilization structure when theobject is grasped).

At block 514, the actuators may be inflated to deform the target objectaround the stabilization device. The actuators may be inflated bysupplying an inflation fluid to the actuators (e.g., through tubing oranother delivery mechanism that supplies the inflation fluid into theinner void of the actuator). As the actuators are inflated, they maymake contact with (e.g.) the ends of the target object, curling thetarget object around the stabilization device. In other embodiments,portions of the target object may be pushed into the stabilizationdevice directly. In either case, the target object may begin to deformaround the stabilization device. In some embodiments, the action of theactuators may cause material inside the target object to becomedistributed between ridges on the stabilization device.

At block 516, the target object may continue to assume the shape of thestabilization device until, at block 518, the system identifies that theinflation limit has been reached (or that the inflation amount, ordegree of extension for a hard actuator, is within the range identifiedin block 508).

Having thus secured the target object in the grip of the end effector,at block 520 the end effector may be translated and/or rotated to movethe target object to a desired destination or configuration.

The above-described technique may be employed with thepreviously-described stabilization devices. However, as alluded toabove, other configurations of stabilization devices may be used for avariety of purposes. FIGS. 7A-7D depict alternative configurations forthe stabilization devices.

Whereas the stabilization devices depicted in FIGS. 3A-3D utilize one ormore extended areas or ridges provided along a single axis, thestabilization devices of FIGS. 7A-7D include extended areas or ridgesprovided along multiple axes. For instance, FIG. 7A depicts astabilization device including a first ridge 702 extending along a longaxis of the base 208 of the stabilization device, and a second ridge 704perpendicular to the first ridge. This may define four openings orquadrants into which actuators may be deployed upon inflation orextension. The actuators may be arranged around the stabilization deviceto effect such a grip.

FIG. 7B depicts a similar example in a double-cross pattern. In thisexample, the first ridge 702 extends along the length of the base 208,but is intersected at two locations by perpendicular ridges 704-1, 704-2(in other embodiments, additional perpendicular ridges, or ridges alongthe long axis, may be provided). The intersection points may be selectedto define a first distance d1 (between the end of the first ridge 702and the first perpendicular ridge 704-1), a second distance d2 (betweenthe first perpendicular ridge 704-1 and the second perpendicular ridge704-2), and a third distance d3 (between the second perpendicular ridge704-2 and the opposing end of the first ridge 702). These distances d1,d2, d3 may be selected so as to define a set of gaps 706-1, 706-2,706-3, 706-4, 706-5, 706-6 into which material from the target objectmay be pushed, compressed, or otherwise secured. A height h of thevarious ridges may be selected to provide sufficient space based on thematerial to be manipulated. The actuators 100 may be deployed in aconfiguration around the stabilization device so as to encourage thematerial into the gaps 706-i.

These configurations allow the contents of a target object, such as abag of material (e.g. chemical powder, rice, grains, etc.), to besubdivided into multiple clumps that the actuators may “brick” into asemi-rigid structure during momentary handling.

The configuration of the actuators 100 may be determined based on thelocation of the gaps into which material is to be encouraged and/orridges onto which the material is to be held by the actuators 100.Compare, for example, the configuration of the actuators used inconjunction with the double-cross stabilization device 708 of FIG. 7C tothe configuration of the I-beam stabilization device 710 of FIG. 7D.FIGS. 7E-7F depict another alternative, in which the ridge of thestabilization device 712 takes the form of a ring around a hollowed-outcentral portion.

Turning to FIGS. 8A-8B, an exemplary fastening mechanism 802 forfastening the stabilization device to the end effector is depicted. Thefastening mechanism 802 may be in the shape of a ridge deployed betweentwo ridges 210 of the stabilization device. Depending on theapplication, the fastening mechanism 802 may be sized and shaped so asto not interfere with the target object when the target object isgrasped by the actuators, or so as to provide an additional surfaceagainst which the target object may be pressed.

The fastening mechanism 802 may include one or more threaded openings804 for receiving bolts passed through the base 208 of the stabilizationdevice and/or through the base of the end effector. The bolts may bescrewed into the threaded openings 804, thus holding the fasteningmechanism 802 against the base 208.

Other shapes or configurations for the fastening mechanism 802 may alsobe employed.

In the example above from FIGS. 4A-4I, the target object was curledaround the stabilization device, and the edges of the target object werepushed, by the distal ends of the actuators, into the sides of thestabilization device body. FIGS. 9A-9C depict an alternativeconfiguration in which portions of the main body of the target objectare secured between the distal ends of the actuators and the tip of thebody of the stabilization device.

In this example, the base 902 of the end effector may be secured to theremainder of the robotic system via a pedestal 904, which may include apassage for providing inflation fluid to the actuator 100. The base 902may include a flange 906 extending from the body of the base 902 by aheight h and a width w. A target region 910 may be provided at the endof the flange closest to the distal end 110 of the actuator 100 when theactuator 100 is in an inflated or deployed state. The width 906 and ashape of the target region 910 may define an area against which thetarget object is pressed by the actuator 100. The height h may define anamount of space 908 between the actuator 100 distal end 110 (when in theinflated state) and the end of the flange. This amount of space 908 maybe varied depending on the nature of the target object to be grasped.

This configuration provides an anvil-like feature at a specific locationrelative to each actuator 100 to allow each actuator 100 to compress atarget object including a container (e.g., a bag) and some of thecontents provided in the container against the anvil-like feature toestablish an improved grip on the target object.

As shown in FIG. 9B, a stabilization device having a center rib keel maybe employed when the actuator 100 spacing (defined by a width w betweenbases or hubs of corresponding facing actuators 100) is fairly closetogether (e.g., less than 140 mm, or more preferably 80-120 mm) on aparallel style gripper. When the actuator spacing is widened on aparallel gripper for larger size bags (e.g., to a width of 140 mm orgreater), then a dual rib stabilization device may be used since itprovides a similar structure for each row of fingers to squeeze theproduct against as the single center rib did in the smaller fingerspacing configuration. Like the original stabilization device concepts,these stabilization devices may aid in locking the product in placewhile soft robotic actuators curl under the target object and encouragethe target object up into the stabilization device to both stabilize thetarget object during high speed handling motion and improve the graspquality on the product (reducing shifting contents that flow aroundwhere the soft robotic fingers are contacting the product bag, whichleads to product pooling below the grasp location of the soft roboticactuators).

FIGS. 10A-10D depict this principle in operation. In these examples,parallel actuators 100 are spaced apart by a width w₁ that is less thana width w₂ of a target object 302 to be grasped (e.g., where w₂ isperpendicular to a long axis of the target object). In this example, thestabilization device body 210 is lowered so as to be just above (e.g.,not in direct contact) with the target object 302 (FIG. 10A). Upon beingdeployed, the distal ends 110 of the actuators 100 may curl around anunderside of the target object 302, forcing the ends 404 of the targetobject up around the body 210 of the stabilization device (FIGS.10B-10C). Upon reaching the inflation limit (FIG. 10C), the targetobject 302 is bent around the body 210 of the stabilization device untilit locks, with the contents of the target object 302 being jammedagainst the stabilization device and the container for the contentsbeing taut. In some embodiments, the inflation limit may be definedbased on a bend limit for the container, representing a maximum degreeof bending that is permissible before the container splits or breaks.

As can be seen in these examples, the target region of the stabilizationdevice body 210 against which the target object 302 is to be squeezedmay be at the tip of the body 210, as in FIGS. 9A-9C, and/or may bealong the sides of the stabilization device body 210, as shown in FIGS.10A-10D.

General Notes on Terminology

Some embodiments may be described using the expression “one embodiment”or “an embodiment” along with their derivatives. These terms mean that aparticular feature, structure, or characteristic described in connectionwith the embodiment is included in at least one embodiment. Theappearances of the phrase “in one embodiment” in various places in thespecification are not necessarily all referring to the same embodiment.Moreover, unless otherwise noted the features described above arerecognized to be usable together in any combination. Thus, any featuresdiscussed separately may be employed in combination with each otherunless it is noted that the features are incompatible with each other.

With general reference to notations and nomenclature used herein, thedetailed descriptions herein may be presented in terms of programprocedures executed on a computer or network of computers. Theseprocedural descriptions and representations are used by those skilled inthe art to most effectively convey the substance of their work to othersskilled in the art.

A procedure is here, and generally, conceived to be a self-consistentsequence of operations leading to a desired result. These operations arethose requiring physical manipulations of physical quantities. Usually,though not necessarily, these quantities take the form of electrical,magnetic or optical signals capable of being stored, transferred,combined, compared, and otherwise manipulated. It proves convenient attimes, principally for reasons of common usage, to refer to thesesignals as bits, values, elements, symbols, characters, terms, numbers,or the like. It should be noted, however, that all of these and similarterms are to be associated with the appropriate physical quantities andare merely convenient labels applied to those quantities.

Further, the manipulations performed are often referred to in terms,such as adding or comparing, which are commonly associated with mentaloperations performed by a human operator. No such capability of a humanoperator is necessary, or desirable in most cases, in any of theoperations described herein, which form part of one or more embodiments.Rather, the operations are machine operations. Useful machines forperforming operations of various embodiments include general purposedigital computers or similar devices.

Some embodiments may be described using the expression “coupled” and“connected” along with their derivatives. These terms are notnecessarily intended as synonyms for each other. For example, someembodiments may be described using the terms “connected” and/or“coupled” to indicate that two or more elements are in direct physicalor electrical contact with each other. The term “coupled,” however, mayalso mean that two or more elements are not in direct contact with eachother, but yet still co-operate or interact with each other.

Various embodiments also relate to apparatus or systems for performingthese operations. This apparatus may be specially constructed for therequired purpose or it may comprise a general purpose computer asselectively activated or reconfigured by a computer program stored inthe computer. The procedures presented herein are not inherently relatedto a particular computer or other apparatus. Various general purposemachines may be used with programs written in accordance with theteachings herein, or it may prove convenient to construct morespecialized apparatus to perform the required method steps. The requiredstructure for a variety of these machines will appear from thedescription given.

It is emphasized that the Abstract of the Disclosure is provided toallow a reader to quickly ascertain the nature of the technicaldisclosure. It is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description, it can be seen thatvarious features are grouped together in a single embodiment for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimedembodiments require more features than are expressly recited in eachclaim. Rather, as the following claims reflect, inventive subject matterlies in less than all features of a single disclosed embodiment. Thusthe following claims are hereby incorporated into the DetailedDescription, with each claim standing on its own as a separateembodiment. In the appended claims, the terms “including” and “in which”are used as the plain-English equivalents of the respective terms“comprising” and “wherein,” respectively. Moreover, the terms “first,”“second,” “third,” and so forth, are used merely as labels, and are notintended to impose numerical requirements on their objects.

What has been described above includes examples of the disclosedarchitecture. It is, of course, not possible to describe everyconceivable combination of components and/or methodologies, but one ofordinary skill in the art may recognize that many further combinationsand permutations are possible. Accordingly, the novel architecture isintended to embrace all such alterations, modifications and variationsthat fall within the spirit and scope of the appended claims.

CONCLUSION

Any or all of the above-described techniques may be implemented bysuitable logic stored on a non-transitory computer-readable medium. Whenexecuted by one or more processors, the logic may cause the processorsto perform the techniques identified above. The logic may be implementedfully or partially in hardware. The logic may be included as part of acontroller for controlling the actuation, de-actuation, movement,position, etc. of a soft robotic actuator and/or a soft robotic systememploying one or more actuators in a gripper arrangement.

The invention claimed is:
 1. A stabilization device for a robotic endeffector comprising first and second robotic actuators capable of movingbetween an undeployed state and a deployed state by curving along acentral axis of rotation, respective distal ends of the first and secondrobotic actuators being brought into proximity with a palm region of anend effector base when the first and second robotic actuators are in thedeployed state, wherein: the first robotic actuator has a first actuatorbase on a radially interior side of the first robotic actuator and thesecond robotic actuator has a second actuator base on a radiallyinterior side of the second robotic actuator, the first robotic actuatorand the second robotic actuator base are deployed on the robotic endeffector so that the first actuator base and the second actuator baseare parallel to each other and in a facing configuration when the firstrobotic actuator and the second robotic actuator are in the undeployedstate, and the palm region comprises a space on the end effector basebetween the first robotic actuator and the second robotic actuator, thestabilization device comprising: a stabilization device base sized andshaped to fit in the palm region of the robotic end effector; and atleast one ridge extending away from the stabilization device base by aheight, the ridge having a length extending parallel to the central axisof rotation of the first and second robotic actuators, wherein the atleast one ridge has a side that is concave or flat and defines a targetarea that is positioned so that, when the first and second roboticactuators are in the deployed state, at least a portion of a targetobject is provided in the target area and is secured in place betweenthe distal ends of the first and second robotic actuators and the targetarea, respectively, wherein the at least one ridge is a first ridge, andfurther comprising a second ridge extending perpendicular to the firstridge.
 2. The stabilization device of claim 1, wherein distal tips ofthe actuators push respective ends of the target object around the firstridge of the stabilization device.
 3. The stabilization device of claim1, wherein distal tips of the actuators push at least a portion of thetarget object into the first ridge.
 4. The stabilization device of claim1, further comprising a third ridge extending parallel to the firstridge.
 5. The stabilization device of claim 1, wherein the second ridgeis one of a plurality of perpendicular extending second ridgespositioned so that gaps are formed between the second ridges, the firstand second robotic actuators configured to push the target object intothe gaps to distribute material included in the target object into thegaps.
 6. The stabilization device of claim 1, further comprising a thirdrobotic actuator, and wherein the palm region comprises a space on theend effector base between the three robotic actuators into which theactuators extend when deployed.
 7. A method comprising: affixing thestabilization device of claim 1 to the robotic end effector; andactuating the first and second robotic actuators to grasp the targetobject between the robotic actuators and the first ridge.
 8. The methodof claim 7, further comprising providing soft robotic actuators as therobotic actuators.
 9. The method of claim 8, further comprisinginflating the soft robotic actuators to a pressure of 9-13 pounds persquare inch (PSI).
 10. The method of claim 7, further comprisingpositioning the robotic end effector so that a long axis of the firstridge of the stabilization device aligns with a long axis of the targetobject.
 11. The method of claim 10, further comprising reverse-actuatingthe first and second robotic actuators prior to moving the stabilizationdevice into position.
 12. The method of claim 7, further comprisingmoving the stabilization device into contact with the target objectbefore actuating the actuators.
 13. The method of claim 7, furthercomprising moving the stabilization device so that the stabilizationdevice is spaced away from the target object but within a predetermineddistance range prior to actuating the actuators.
 14. The method of claim7, further comprising translating or rotating the robotic end effectorwhile grasping the target object, the translating or rotating pushingthe target object into the first ridge of the stabilization device.